Robust missile defense relies on an array of complementary assets performing diverse surveillance and engagement tasks against ballistic missile attack. The engagement or destruction of a hostile ballistic missile requires that the missile be detected and its trajectory estimated, and possible means for engagement identified. The destruction also requires that from among the identified means for engagement or assets, at least one be selected for use. Once one or more assets are identified for use in engaging the missile, an intercept path must be defined for the interceptor, based on the projected location of the missile at the time of interception.
Several Ballistic Missile Defense (BMD) assets are currently available, including sea-based Aegis, land-based Theater High Altitude Area Defense (THAAD), and Patriot. Each of these assets has its own associated planner which independently generates its mission plan.
FIG. 1 is a simplified representation of the ballistic missile defense (BMD) problem, showing a littoral (shallow-water) region between a land mass and sea region, and also showing a defended area and known locations from which attacking missile can or might be launched. The physical problem can be understood by reference to FIG. 1. In FIG. 1, a sea region 12 lies adjacent a land mass 14 defining a shoreline 16. A defended region is designated 18. The operating region for sea-based defensive platforms lies in sea area 12, and is designated 20. The operating region for land-based defensive assets is designated 22. An adversary is expected to launch ballistic missiles from a set of launch areas whose positions are known, which are designated 24a and 24b. The missiles, when launched, fly along trajectories, designated generally as 25a and 25b, to a set of defended areas, one of which is designated 18. A set of assets is assigned the mission to protect these defended areas. Each asset type (e.g. land based, sea based) is constrained to operate within some pre-specified region. These regions, known as operating areas, satisfy several operational constraints. For land based systems, the sensors and interceptors must be located on suitable terrain, away from enemy territory. Sea based sensors and interceptors are located away from commercial shipping lanes and littoral areas controlled by the adversary.
FIG. 3 illustrates the same region as FIG. 1, and corresponding elements are designated by like alphanumerics. In this case, corresponding to the prior art, a single asset, namely asset 220, has a sensor arrangement which is capable of “deploying” a surveillance volume 240, and is also capable of launching an intercepting missile 250 for destroying the ballistic missile threat. Asset 220 detects the threat by observing surveillance volume 240, tracks the threat along at least a portion of its track 25a, and supports the interceptor 250 launched from a land-based asset 220 It is irrelevant to the issues whether the sensors and interceptors are land or sea based. The requirements associated with this engagement sequence are very stringent and this defense mode may not be possible or effective for all possible attacks.
Improved or alternative missile defense methods are desired.